Erosion Processes on Arid Minespoil Slopes
- Roy C. Sidle ,
- R. W. Brown and
- B. D. Williams
Surface wash and dry ravel erosion rates from minespoil were measured for 4.7 yr after initial reclamation at a site in western Nevada. Average annual total erosion from all 15 plots ranged from 0.48 to 1.10 Mg ha−1. Neither mulching treatment nor slope gradient (3:1 vs. 2:1) significantly affected surface wash from reclaimed minespoils. About 70% of the total wash load from the entire study period occurred during two midsummer to autumn periods (1989 and 1990) in which the most intense storms occurred. Southwest-facing slopes (windward) had significantly higher surface erosion compared with northeast-facing slopes (leeward). The higher surface roughness encountered on 2:1 slopes appeared to more effectively control surface wash than gentler (3:1) slope gradients or early-stage vegetative cover. Straw mulch significantly reduced ravel erosion from the relatively smooth 3:1 slopes. Mulch treatment was not effective in reducing ravel erosion from rougher, 2:1 slopes. Windward (southwest-facing) slopes had significantly higher ravel erosion than northeast-facing slopes. Ravel rates were not as directly affected by rainfall intensity as were surface wash rates. Regressions of surface wash with EI (rainfall energy-intensity factor) were best with short-term intensities (i.e., EI5, R2 = 0.94); regressions of ravel with EI were best using longer term intensities (EI30; R2 = 0.83). Except for very dry collection periods (including autumn to spring), surface wash exceeded ravel.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .